virtualeast
Newbie level 1
load switching relay
Hello All,
I'm trying to find a Relay, preferably Solid State, that can handle delivering and switching high voltage/High current to and from a bank of capacitors.
To simply put it, i am trying to charge multiple capacitors (concurrently) with one set (3 bank) of relays and switch between each capacitor bank to discharge into a Flash Lamp with another set of relays (3 bank). Just like charging "Low Charge" batteries and choosing between them for controlling a device.
The spec's are these:
Charge side:
500Vdc Power supply to charge each capacitor and shut off
when desired voltage reached.
7Amp charge current into each capacitor until shutoff.
Discharge side:
Max 500Vdc on the capacitor into the flash lamp head.
Large Surge current for short time. No more then ~25A/Sec.
So essentially, there are 3 capacitors, 3 charge control relays, and 3 capacitor bank selectors. The control system is a microcontroller based system which monitors the charge and bank selector with either 5 volts or 12volts though a transistor. I've found and tried to use a lower dc voltage based contact relay, but when the voltage exceeds 300vdc, the discharge feeds back into the control coil from the surge of energy rushing through and resets the control system and with prolonged use, destorys the relay. I also have an inline fast-blow fuse of 20A with the discharge into the lamp head and does not break (shows an inrush of less then 20amps/sec).
I've searched the internet far and wide and found little to nothing of these specs. Although I have found Mosfets that support this voltage and current but am having difficulties trying to find a soltion in finding a way to make Mosfets work like a relay or load switch. FYI, there are two relays per capacitor, one for charging and one for bank selection, so i cannot do lowside driving with any switching circuit (Seperating ground from the capacitor). Highside driving seems to be the solution but seems to be difficult as the capacitor voltage rises the source voltage rises which means the gate voltage has to follow (rated voltage of +- 30VGS).
I'll post up a few ideas i have with the mosfets once I draw them out.
I'm hoping someone has anyidea of how to do this unique idea of switching high voltage/high current and speaks out. Thanks for your help!!
Hello All,
I'm trying to find a Relay, preferably Solid State, that can handle delivering and switching high voltage/High current to and from a bank of capacitors.
To simply put it, i am trying to charge multiple capacitors (concurrently) with one set (3 bank) of relays and switch between each capacitor bank to discharge into a Flash Lamp with another set of relays (3 bank). Just like charging "Low Charge" batteries and choosing between them for controlling a device.
The spec's are these:
Charge side:
500Vdc Power supply to charge each capacitor and shut off
when desired voltage reached.
7Amp charge current into each capacitor until shutoff.
Discharge side:
Max 500Vdc on the capacitor into the flash lamp head.
Large Surge current for short time. No more then ~25A/Sec.
So essentially, there are 3 capacitors, 3 charge control relays, and 3 capacitor bank selectors. The control system is a microcontroller based system which monitors the charge and bank selector with either 5 volts or 12volts though a transistor. I've found and tried to use a lower dc voltage based contact relay, but when the voltage exceeds 300vdc, the discharge feeds back into the control coil from the surge of energy rushing through and resets the control system and with prolonged use, destorys the relay. I also have an inline fast-blow fuse of 20A with the discharge into the lamp head and does not break (shows an inrush of less then 20amps/sec).
I've searched the internet far and wide and found little to nothing of these specs. Although I have found Mosfets that support this voltage and current but am having difficulties trying to find a soltion in finding a way to make Mosfets work like a relay or load switch. FYI, there are two relays per capacitor, one for charging and one for bank selection, so i cannot do lowside driving with any switching circuit (Seperating ground from the capacitor). Highside driving seems to be the solution but seems to be difficult as the capacitor voltage rises the source voltage rises which means the gate voltage has to follow (rated voltage of +- 30VGS).
I'll post up a few ideas i have with the mosfets once I draw them out.
I'm hoping someone has anyidea of how to do this unique idea of switching high voltage/high current and speaks out. Thanks for your help!!